KLT for an Expanding Universe with SETI Applications

The relativistic KLT was first considered by one of the authors as early as the 1990s, but that was confined to special relativity only. In this paper, we attempt, for the first time, to extend the KLT calculations to the Friedman-Lemaitre-Robertson-Walker (FLRW) metric of the expanding universe. It is claimed that our new results could be of interest for SETI applications about incoming signals from receding galaxies.